The `repository` field must specify a repository where the Tree-sitter grammar should be loaded from, and the `rev` field must contain a Git revision to use, such as the SHA of a Git commit. If you're developing an extension locally and want to load a grammar from the local filesystem, you can use a `file://` URL for `repository`. An extension can provide multiple grammars by referencing multiple tree-sitter repositories.

## Tree-sitter Queries

Zed uses the syntax tree produced by the [Tree-sitter](https://tree-sitter.github.io) query language to implement
several features:

- Syntax highlighting
- Bracket matching
- Code outline/structure
- Auto-indentation
- Code injections
- Syntax overrides
- Text redactions
- Runnable code detection
- Selecting classes, functions, etc.

The following sections elaborate on how [Tree-sitter queries](https://tree-sitter.github.io/tree-sitter/using-parsers#query-syntax) enable these
features in Zed, using [JSON syntax](https://www.json.org/json-en.html) as a guiding example.

### Syntax highlighting

In Tree-sitter, the `highlights.scm` file defines syntax highlighting rules for a particular syntax.

Here's an example from a `highlights.scm` for JSON:

```scheme
(string) @string

(pair
  key: (string) @property.json_key)

(number) @number
```

This query marks strings, object keys, and numbers for highlighting. The following is a comprehensive list of captures supported by themes:

| Capture                  | Description                            |
| ------------------------ | -------------------------------------- |
| @attribute               | Captures attributes                    |
| @boolean                 | Captures boolean values                |
| @comment                 | Captures comments                      |
| @comment.doc             | Captures documentation comments        |
| @constant                | Captures constants                     |
| @constructor             | Captures constructors                  |
| @embedded                | Captures embedded content              |
| @emphasis                | Captures emphasized text               |
| @emphasis.strong         | Captures strongly emphasized text      |
| @enum                    | Captures enumerations                  |
| @function                | Captures functions                     |
| @hint                    | Captures hints                         |
| @keyword                 | Captures keywords                      |
| @label                   | Captures labels                        |
| @link_text               | Captures link text                     |
| @link_uri                | Captures link URIs                     |
| @number                  | Captures numeric values                |
| @operator                | Captures operators                     |
| @predictive              | Captures predictive text               |
| @preproc                 | Captures preprocessor directives       |
| @primary                 | Captures primary elements              |
| @property                | Captures properties                    |
| @punctuation             | Captures punctuation                   |
| @punctuation.bracket     | Captures brackets                      |
| @punctuation.delimiter   | Captures delimiters                    |
| @punctuation.list_marker | Captures list markers                  |
| @punctuation.special     | Captures special punctuation           |
| @string                  | Captures string literals               |
| @string.escape           | Captures escaped characters in strings |
| @string.regex            | Captures regular expressions           |
| @string.special          | Captures special strings               |
| @string.special.symbol   | Captures special symbols               |
| @tag                     | Captures tags                          |
| @tag.doctype             | Captures doctypes (e.g., in HTML)      |
| @text.literal            | Captures literal text                  |